The rattlesnake Crotalus durissus terrificus (Viperidae: Crotalinae) as an experimental model to study the involvement of peptidases in the survival of spermatozoids

Abstract

The long-term sperm storage in the female genital tract with maintenance of fertilitization capacity are natural events for the snake Crotalus durissus terrificus. Consequently, this snake provides an experimental model with peculiar biomedical interest for the identification of natural factors related to these phenomena. Components from sperm, ducto deferens, and/or uterus and vagina could have a role on the long-term sperm survival in uterus. Probably, peptides and peptidases are important factors, since they have been related to spermatozoa fertility and infection, as well as they can be seem as possible parameters of normal status of these cells. The aims of the present project are (i) to perform the fluorometric screening of enzyme activities of basic (APB) acid (APA), neutral (APN), cystyl (CAP), pyroglutamyl (pGluAP), prolyl-imino (PIP) and prolyl-dipeptidyl (DPPIV) aminopeptidases, and prolyl endopeptidase (PEP) in soluble (FS) and solubilized membrane-bound (FM) fractions from whole semen (and, if possible, also in seminal fractions) stored in uterus or from the ducto deferens, as well as from uterus, ducto deferens and vaginal tissues of this snake, which will be monthly collected during two years, and (ii) to associate these enzyme activity levels with spermatozoal quality and fertilitization capacity, in order to identify a possible relationship between examined peptidases and long-term sperm survival.